Heretofore hearts have been effectively "paced" by electrical pulses applied to the heart, namely to the endocardial wall within the right atrium. However, difficulties have been encountered in locating the extremity of an electrode at the end of a pacing lead in an appropriate location within the right atrium and in a stable manner, even with the benefit of fluoroscopy. In fact, without the benefit of fluoroscopy, it has heretofore been impossible properly to insert a temporary pacing lead with an electrode at the end thereof into the right atrium of a heart.
In view of this inability to effectively locate an electrode at the end of a pacing lead assembly within the right atrium in a stable manner, most pacing electrodes at the end of a pacing lead assembly are inserted into the right ventricle wherein stable positioning of the electrode can be obtained. In this procedure, however, it has been found to be difficult to manipulate a pacing electrode through the tricuspid valve and into the right ventricle without fluoroscopy.
Recently, and as disclosed in U.S. Pat. No. 4,166,469 issued Sept. 4, 1979, there is disclosed an apparatus and a related method for effecting a rapid and generally atraumatic insertion of a pacemaker electrode through the subclavian vein, through the superior vena cava and into the right atrium. The apparatus disclosed utilizes a "J" shaped electrode which it has been found, can be inserted through the right subclavian vein into the right atrium and when the electrode is oriented and manipulated in a predetermined direction and manner, the tip of the electrode will always engage the right atrium in a stable manner.
Also it has been recognized that an electrode having an appropriately oriented bend at the distal end thereof will pass through the tricuspid valve into the right ventricle when it is inserted in a predetermined manner and direction through the right subclavian vein.
It has also heretofore been proposed to provide a wing for orienting and stabilizing the position of the electrode, such orienting and stabilizing wing being mounted on the sheath of the lead connected between the electrode at the distal end of the pacing lead assembly and a terminal member at the proximal end of the pacing lead assembly. Such orienting and stabilizing wing indicates the orientation of the curve or bend situated in the outer end of the pacing lead after the distal end of the pacing lead has been inserted into the heart and can be taped to the patient's skin to stabilize the electrode after electrical contact has been properly established between the tip of the electrode and the heart.
The orienting and stabilizing wing is fixed on the sheath of the pacing lead at a position outside the patient's body when the distal end of the pacing lead has been inserted into the heart. The wing includes left and right wing portions which extend laterally on either side of and from the sheath. The lateral direction of the pair of wing portions, i.e., the plane of the wing, indicates the orientation of the curve or bend in the outer end portion of the pacing lead and indicia are provided on the wing for indicating which side of the wing should be facing away from the patient and which side should be facing the patient's skin. The desired orientation is such that when the plane of the wing is flat against the patient's skin, with the "tape side up" indicia facing upwardly, the J shaped flexible outer end portion of the pacing lead with an electrode at the tip of the distal end thereof, in the case of an atrial electrode, lies in a plane which is transverse to the plane of the wing and at an angle of approximately 90.degree. to the plane of the wing.
Further it has heretofore been proposed in U.S. Pat. No. 4,300,553 to provide a catheter placement assembly with a wing.
The winged assemblies described above each have a three dimensional configuration.
As will be described in detail hereinafter in connection with the description of the present invention, it is desirable that, for packaging, storage and shipping purposes, the pacing lead assembly have a more planar or flat configuration for being placed flush against a packaging substrate. Accordingly, the pacing lead assembly of the present invention differs from the pacing lead assemblies with fixed wings described above by providing a positionable locating wing which is rotatable on the sheath of the lead of the pacing assembly so that it can be rotated to a flat position for packaging of the pacing lead assembly and then, prior to use, be locked in an orienting and locating position on the sheath such that the plane of the curved end portion of the pacing lead has a predetermined orientation to the plane of the wing as will be described in greater detail hereinafter.